Among the procedures involved in diagnosis and treatment of medical conditions involving the biliary tract are those that require the use of a guidewire in order to facilitate advancement of a selected catheter to a selected site in the biliary tract. Typically, such procedures are performed through the working channel of an endoscope. Such procedures include ERCP in which radiopaque contrast liquid is injected into portions of the biliary tract to enable the physician to visualize the anatomy of the tract as an aid in diagnosis. Among the procedures that may be performed are those relating to treatment of an obstructed duct, as may result from tumors, gall stones or other medical conditions. Procedures may be employed to dilate the obstructed region, as with a dilatation catheter, or to remove stones, among others. It has become increasingly common to place a stent in the duct so that after the obstruction in the duct has been treated to restore patency, the stent maintains that patency. Additionally, the physician may wish to place multiple stents in the region of the branched portions of the biliary tract, even if the adjacent portion of the duct has not been and does not need treatment at the time. The decision to place a stent in each of adjacent branches may be prompted by the difficulty in accessing the second branch with a guidewire after a stent has been placed in the first branch. It has been found that after a stent has been placed in one branch of the tract in proximity to the juncture of the branches, considerable difficulty can be expected in trying to place a second guidewire in the other branch. Consequently, it may be preferable to place both stents at the same time. The present invention facilitates such placement as well as provides a versatile catheter usable in other techniques associated with the biliary tract.